Boiler



M. S. HALL BOILER 5 Sheets-Sheet l Filed May l, 1935 9 O 2 3 4 8 6 n 3 n e l 7 r l 4 2 2 Q 3 2 H. /H O l. l; |.I cl2 4 ||.l|| 2 .I 2 l M |I m 3 l|.| All M L V W 5 I n lf f 1/ 9 W MMU, 4 I 3 8 0 6 2 5 8 7 2 w 2 INVENTOR.

M .S HALL FIG. 2

ATTORNEY.

Dec. 29, 1936.

M. s. HALL BOILER 5 sheets-sheet 2 Filed May 1, 1955 INVENTOR.

M. S. HALL ATTORNEY.

Dec. 29, 1936. M s HALL 2,066,275

BOILER Filed May l, 1935 v 5 Sheets-Sheet 5 F\G.7 4 n 64 30 1NVENTOR.

MsHALl. f BY ATTORNEY.

Dec. 29, 1936. M. s, HALL 2,066,275

BOILER Filed May 1, 1935 5 Sheets-Sheet 4 INVENTOR.

M. S* HA LL M. s. HALL 2,066,275

BOILER Filed May 1, '1935 5 sheets-sheet s INVENTOR.

M S. HALL ATTORNEY.

Patented Dec. 29, 1936 UNITED STATES PATENT OFFICE BOILER land Application May 1, 1935, Serial No. 19,284

14 Claims.

'I'his invention relates to boilers and more particularly to internally fired fluid fuel burning boilers.

The object of this invention is to provide a comparatively light, small, compact, self-contained boiler adapted for use with a fluid fuel burner, in which the fuel is burned in a quiet, cleanly manner, in an internal compartment substantially surrounded by water-back surfaces and from which compartment the hot gases are conducted in a circuitous manner to the gas exit of the boiler.

A further object is to provide shallow gas passages of adequate capacity which provide for a maximum contact between the hot gases and the water-backed surfaces, the mean hydraulic depth of the gas passing through such gas passages being held to small values, and the passages so arranged as to minimize draft loss in the long passage of the gas through the boiler.

Other objects of this invention are to provide a boiler in which the quantity of water required for operation is relatively small as compared with an ordinary boiler and in which circulation is rapid and which provides quick heat transfer and quick response to heating requirements, also to provide a boiler adapted for submersion within the water contained therein, of a heat eX- changer for a quick heating hot water supply, also to provide for a steam-to-liquid hot water space heating system in which the transfer of heat from steam to a hot water space heating system takes place within the boiler and in the steam space thereof.

Further objects and advantages will be apparent and the invention be understood by reference to the accompanying drawings which illustrate preferred embodiments of the invention. The

, reference characters on the several drawings in- Cil dicate like or corresponding parts/throughout Fig. 1 is a perspective view of the boiler for use as a steam or hot water boiler without the exchange heater coils.

Fig. 2 is a side elevation, partly in section, of the boiler, shown in Fig. 1, illustrating in part, the internal construction of the boiler.

Fig. 3 is a Vertical cross section on line 3-S of Fig. 2.

Fig. 4 is a. vertical section on line 5 4 of Fig. 2.

Fig. 5 is an enlarged fragmental vertical section on line 5-5 of Fig. 2, illustrating the relief stay tubes.

Fig. 6 is a perspective view of the boiler with parts cut away to show the path of the gases through the boiler.

Fig. 7 is a perspective view, from the rear, of a modiedform ofthe boiler in which the outer shallow gas passage is disposed at the rear of the boiler instead of at the sides of the boiler as A in Figs. 1 to 6 inclusive.

Fig. 8 shows a detached perspective View of combustion chamber partly cut away to show the construction of the tubular portion as well as the refractory lining material, also the connections, and inlet and outlet.

Fig. 9 shows a modied form of combustion chamber, in perspective View, with refractory blocks forming the lining of the combustion chamber, partly cut away to show the construction.

Fig. 10 is a fragmental view partly in elevation, partly in section, of the lower part of a boiler with another modified form of combustion chamber of tubular construction lined with refractory material xed in place and showing structural details.

Fig. 1l is a fragmental View in perspective, showing the location of hot water supply system coil and hot water heating coils.

Fig. 12 shows a fragmental perspective View, partly cut away, of the upper part of the boiler adapted for use with a hot water supply system heat exchanger coil and also a hot water space heating heat exchanger coil and baiile.

Referring now to the drawings, the boiler includes an outer shell I and an inner shell 2 forming between them a water compartment 3. The outer shell has substantially flat sides and top strengthened by stays as needed. The bottom 4 of this shell is of curvilinear transverse section. The inner shell is of cylindrical form, open at one end with the opening in registry with a corresponding opening in the front wall 5 of the outer shell, joined to this front wall and in xed and spaced relation to the other walls of the outer shell. The other end of the inner shell is closedby a ilat plate 6 in steam and water tight relation and this at plate is in spaced relation to the end wall 'I of the outer shell. The space 8 within the inner shell and the space 9 without the outer shell are in communication by means of passages I0 (Figs. 3 and 4) which permit the combustion gases to pass from within the inner shell to the gas space outside of the outer shell. This gas space 9 is bounded at its front and rear ends by vdownward extensions of the front and rear boiler outer shell. closed by plate II and a passage is provided so that the gases pass therefrom to the lower part of the shallow gas flues I2 at the sides of the boiler, and without the outer shell. These shallow iiues are formed on one face, by the outer boiler shell and on the other faces, by a plate I3 with flanged edges I4 which maintain the plate in spaced relation to the outer shell and are joined,

shallow ilues, between the wall of the flue andv 'I'he bottom is' (itlr the outer shell to direct the gases, rst rearwardly, then around the end of the lowermost baffle, then forwardly, and around the end of the uppermost bafe, and then rearwardly to finally exit from the gas cross connection i6 formed across the upper part at one end of the boiler and thegas exit connection il. of the boiler is provided with partitions I8 and I9 to form the cross gas connection. The gas cross connection is suitably positioned so as to permit the gases from the shallow gas flues to exit at the gas exit connection.

The combustion chamber which is within the boiler structure is substantially cylindrical in form, open at both ends and comprises a lining 20 of refractory material presented to the flame and a water compartment consisting of tubes supporting the refractory material lining. The water compartment is connected at the inner end by the inlet tubes 2! and the outlet tubes 22 to the boiler water compartment, the inlet and outlet tubes affording circulation communicompartment is preferably in two parts, a right and a left hand side.

Each -of these parts comprises the substantially horizontally disposed inlet tube 2| to the combustion chamber water compartment and its corresponding manifold 23, and the outlet tube 22 and its manifold 2d and the'connecting tubes 25 which connect the twoY manifolds for circulation. These tubes are curved and of substantially arcuate form. These tubular water compartments support the cylinder of refractory material which forms the combustion chamber lining and within which the combustion of the fuel takes place. The combustion chamber is maintained in spaced relation to the inner cylindrical boiler shell by means of the inlet and outlet tubes, so that gases pass freely from the combustion chamber, around its far end and forward between the inner cylindric shell of the boiler and the outer side of the combustion chamber water compartment, to the gas passage openings I0 at the forward portion of the boiler (see Fig. 6). The open forward end of the combustion chamber is partially closed by a ring l26 vof refractory material in substantial coaxial registration with the lining 2B, and is provided with an opening 21 through which the fuel of an oil burner and combustion air are introduced.

The open forward end of the inner shell of the boiler where it joins the front outer boiler shell is closed by a plate 28 which covers the opening and which also has an opening in registry with the opening in the yrefractory ring so that the fuel and combustion air of the burner may enter therethrough into the combustion chamber; the burner housing (not shown) is secured to this plate and the joint between the plate and the boiler is made gas tight. The space between the refractory ring, the cover plate 28 and the burner housing is filled in with an insulating material Sil, such as asbestos, mineral wool or like material.

The outlet of the combustion chamber water compartment communicates with a receptacle 29 within the boiler water compartment. This receptacle is closed at its lower end and open at its upper end, and may be of any suitable cross section. Its upper end is positioned just below the usual level of the boiler water, so that water from the combustion chamber water compartment entering this receptacle must pass upward The outer shell into the boiler water, which conduces to rapid circulation between the boiler and the combustion chamber water compartment and causes the boiler to heat up quickly to operative condition.

Water enters the boiler at inlet 3Q and steam or water, as the case may be, passes out of the boiler at outlet 3|. The boiler stands on legs 32. The boiler is supplied with asight hole 33 and cover 34 and a clean out door 35, (Fig. l) affording access to the gas passages and also with the sun-dry accessories usual with such boilers, such as a steam or pressure gage, water column and safety or relief devices. The outside of the device is covered with a layer of insulating material and may also be supplied with a casing or cover. (Not shown in the drawings.) Y

The boiler provides a large and effective heat transfer area and utilizes a high percentage of the available heat in the fuel. The exit gas ternperature is low and draft resistance in the boiler is minimized so that economy and efficiency are at a maximum.

The operation of the boiler is as` follows: Ignition of the fuel may be as desired and takes place in the combustion chamber at the forward end and it is completely burned within the chamber. The hot gases pass rearwardly and outwardly around the inner end of the combustion chamber between it and the closed end of the inner shell. The gases then pass forward in the gas pass 8 between the outer face .of the cylindric combustion chamber and the inner cylindric shell of the boiler, to the .forward end of the boiler. The gases then pass outwardly through the communication passages l0 and enter the f lowest gas pass 9, which is without the outer boiler shell (see Fig. 6); the gases then enter the shallow side gas passes and are there directed in a circuitous manner, by the baflles I5, to thev up,- per part of the shallow side gas passes where they travel on one side of the boiler to the cross gas pass I6 located toward the top at one end of the boiler and thence to the gas exit Il, and travel on the other side of the boiler directly to the gas exit. l

'I'he water in the boiler main water compartment is heated by the contact of the boiler shell with the hot gases. The boiler water enters the combustion chamber water compartment at inlet 2l and circulates therethrough., and then passes out into the boiler at outlet 22 which is so disposed with respect to receptacle 29 as to direct the flow of heated water to the upper portion of the boiler. The heat exchange in the com# bustion chamber water compartment takes place on the inner face of the combustion chamber by heat of the flame conducted through the refractory lining to the tubular water chamber, and also on the outer face of the combustion chamber tubes directly from the gas passing over the` exposed portions Vof the tubes of said chamber, (see Figs. 2 kand 6).

The use of a hot water supply coil or a hot water heating system exchange coil or both is pro-v vided for and is preferably accomplished as set forth below.

The boiler is particularly adapted as a steam boiler for dual use in connection with the hot water supply system coil 35 and the hot water space heating system coil 31 shown in the frag-l water outlet tubes 40 pass, in water and steam 75` tight relation. The cover plate is fixed in position and made water and steam tight by means of gaskets and screws. The hot water supply system is connected with the coil inlet and outlet. The coil 35 is positioned within the boiler, its operative position being below the usual level of the boiler water. The boiler` water contacting this coil causes heat to be conducted to the water contained within the coil thus providing a hot water supply.

The hot water space heating system coil 31 comprises a manifold chamber 4l with dividing wall 42 separating the chamberk into inlet and outlet manifolds 43 and 44, a tube plate 45 with a series of individual tubes A5 fixed thereto, the lower ends 41 of which are secured in water and steam tight relation in the tube plate in open communication with the manifold inlet chamber 43, the upper ends 48 of the tubes being made fast similarly in the tube plate 45 in open communication with the manifold outlet chamber lill, and inlet and outlet connections 49- and 55 from the heating system to the manifold and from the manifold to the heating system. The manifold chamber and tube plate are fastened together and the two are secured to the outer boiler shell in water and steam tight relation at an opening in the boiler shell through which the hot water heating system coil is introduced. The heat exchange tubes of this coil 31 are positioned so as to lie wholly in the steam space of the boiler, so that the water of the hot water space heating system, which is connected for circulation through this heat exchange coil, is heated by the steam generated in the boiler which contacts with this coil. The upper walls of the sha1- low side gas passages I2 as well as the cross gas passage I6, in contact with the steam space, provide a certain amount of superheat to the steam formed when the boiler is provided with this heat exchange coil, the open top box-like bafe 5| adjacent to and extending from the walls of the boiler outer shell below this heat exchange coil is so positioned as to separate the said upper from the lower portion of the steam space and to provide communication between this upper dry chamber in which the coil is positioned, and the lower saturated steam chamber. This steam space is provided with an air relief valve 1l, which permits escape of air which may be trapped in the steam space. As soon as heat passes from the steam into the water within the coil 31, circulation begins in the hot water heating system and as the amount of water contained within this type of system is not as great as in the ordinary hot water boiler, the system becomes fully operative within a comparatively short period of time.

In positioning these coils in the boiler, I cut away portions of the outer shallow gas passages and of the outer boiler shell so as to provide for openings through which the coils are introduced. The boiler shell about these openings is provided with threaded holes for bolts or screws to x the manifold and tube plates in operative position.

Either or both of these heat exchanger coils may be used to good advantage in connection with the boiler.

A modication of the internal combustion chamber is shown in Fig. 9. This combustion chamber comprises a substantially cylindric Water compartment with inner and outer cylindric plates 52 and 53 in spaced relation providing an enclosed water space 54 between them. This hollow cylindric chamber is provided with inlet and outlet tubes 55 and 56, connecting it for circulation with the water in the boiler. The fire facing surface of the water compartment is provided with a lining of refractory blocks 5l xed in place by means of a refractory cement or by interlocking joints. Internal baies 58 provide means for directing the flow of water within the water jacket so that the entering water traverses the length of the water jacket below, rises at the forward end of the baiiles and passes rearwardly above the baffles to the outlet.

The forward end of the combustion chamber is closed by the ring 26 of refractory material and the relative positions and the operation with respect to the other parts of the boiler remain the same.

A second modified form of the combustion chamber is shown in Fig. 10. The Water compartrnent in this modification consists of a series of U shaped tubes 55 each of which is in open communication for circulation at its lower end Sil and at its upper end 6I with the main water compartment 3 of the boiler. Each tube comprises a straight lower portion, a bent middle portion in substantially semi-circular arcuate form, and a straight upper portion. 'Ihe lower end of each tube is fixed in a registering opening in the inner boiler shell, which shell in this modification is of polygonal cross section. The upper end also is fixed in a similar manner to the inner boiler shell, so that each tube is separately connected at a high and low point for circulation with the boiler. The bent portion of the tube is maintained by these fixed ends in concentric and spaced relation to the inner boiler shell.

The first of the tubes is connected to the inner shell as described above on one side of a central, longitudinal, vertical plane and the next tube on the opposite side of the shell, so that the bent portions of the tubes form two banks, on opposite sides of said plane, alternate tubes lying in the same bank, the concave faces of the U shaped tubes forming a substantially cylindric support to which is applied a refractory material lining providing a combustion chamber in which combustion of the fuel takes place and is completed. K

'Ihe spaced relation `between the rear end of the combustion chamber and thev flat end plate 6 forming the rear wall of the inner shell of the boiler, is maintained by omitting the rear tubes of the combustion chamber and the corresponding refractory material blocks.

The forward end of the combustion chamber is supplied with a refractory material ring. Circulation is maintained through each tube individually and is free and rapid and well distributed in the boiler. The tube ends, where they are xed in the inner shell of the boiler, are accessible from the outside of the boiler by means of the detachable cover plate 62 and the threaded plugs 63 which screw into threaded openings in the outer boiler shell which openings permit access to the open tube ends which are positioned opposite the threaded openings. The curved tubes in this form of combustion chamber expand and contract freely under varying conditions of temperature and this puts little strain on the tube ends where they join the shell, which tends to make a secure, permanently tight, joint.

A modified form of my boiler is shown in Fig. 7, according to which the side gas passages are omitted. The outer shell of the boiler extends downwardly so that the extension joined to the bottom plate forms a gas tight passage between the boiler outer shell and the bottom plate from front to rear. This passage connects through an opening 64 in the rear outer shell extension with a shallow substantially vertical gas passage 65 which directs the gases into a crosswise disposed gas passage 66 above and toward the rear of the outer boiler shell and this gas passage leads to the gas exit 61. The gases are directed upward in the rear shallow gas pass by means of the baffles 68 which direct the gases so as to pass upward in a circuitous path to the crosswise .disposed passage and thence to the exit. This modified form of the boiler is particularlyadapted for use with the combustion chamber shown in Fig. 10. The boiler may be provided with one or both Vside gas passages in addition to the rear shallowgas passage, in which case the arrangement of the baiiles may be varied as required so as to direct the gases toward the exit.

In the use of the boiler, I have found that it yields a high eflicency, which is evidenced by low exit gas temperatures and high output of heat as compared with input. The fuel is completely consumed without smoke or soot. There is ample gas passage for normal combustion notwithstanding the long and circuitous channels in which the gas must travel. However, in the use of fluid fuel burners with forced draft and with automatic control and under intermittent conditions of operation, it is not unusual that, due to sudden changes in combustion rate, a large volume of gases of combustion must be taken care of These changes in combustion rate are evidenced by combustion pulsation and cause noisy operation which is very objectionable in domestic heating installations and otherwise undesirable. A back load is put upon the forced draft fan and occasionally in consequence of an unusual volume of gas may approach Violence. To relieve and to obviate such a condition, I provide a series of relief channels or passages 69 Fig.' 5, each of which consists of a tube 'l0 passing through the boiler water compartment connecting the gas passages between the inner boiler shell and the combustion chamber with the gas passage without the boiler outer shell. The respective ends of these tubes vare fixed to the inner and to the outer boiler shells in steam and water tight relation. These tubes also serve to strengthen and to stay the boiler shells. As the tubes are relatively short as compared with their diameter, they offer but slight resistance to gas passag-e under pressure and are of small effective area in comparison with the area of the gas passes themselves so that l during the normal gas passage, the relief funcgas production, the relief tubes relieve this con-cli tion, the gases pass through these cut-off or shunt tubes, as it were, from an area of high presr sure near the combustion chamber to an area of lower pressure farther away, the relief tubes making in fact a short cut for the passage of an increased proportionate amount of the gases, 'I'his has been found to be effective and satisfactory, providing an even, non-fluctuating flame and non-pulsating air flow into the combustion chamber, an undiminished and uniform air and gas flow, and also an effective means to prevent sooting and consequent short-circuiting of burner ignition electrodes and of the burner parts by back flow of gas and other combustion products.

What I claim and what I desire to secure by Letters Patent isz- 1. A water heater comprising an outer shell and an inner shell forming therebetween a main water heating compartment, the said outer shell of substantially rectangular section, the inner shell of substantially hollow cylindric form, said inner shell open at its forward end and in registry with a corresponding opening in one wall of the outerv shell and joined at said end, in water and steam tight relation, to said outer shell, the rear end of said inner shell closed by a substantially flat plate in spaced relation to the rear end of the outer shell; a combustion chamber, within and in spaced relation to said inner shell, said chamber comprising a substantially cylindric horizontal refractory lined water compartment connected at high and low points to the main water heating compartment, a ring of refractory material disposed in the forward end of said chamber, saidY ring opening providing for the introduction of fuel and air of a uid fuel burner; means to pass the products of combustion from Said chamber, said means comprising a circuitous passage for the gases from said chamber into a restricted space without the inner shell, and thence through substantially vertical narrow gas passes to a gas exit passage in the upper part of the boiler.

2. A boiler comprising an outer shell of rectangular section in its upper portion, cylindric in its lower portion, an inner shell of substantially hollow cylindric form closed at one end, open at the other, said open end joined to one wall of said outer shell provided with a registering opening therefor; said inner shell maintained by said joint in spaced relation to the other walls of the outer shell and in gas and water tight relation thereto; stays supporting the surfaces of the inner and outer shells; a boiler water compartment enclosed between said shells, provided with inlet and outlet; a combustion chamber compris,- ing a substantially cylindric, horizontally disposed, refractory material chamber, supported and maintained in spaced relation within said inner shell by a hollow substantially cylindric auxiliary water heating compartment of tubes, said compartment connected for continuous and open circulation with the boiler water compartment by inlet and outlet connections at high and at low points and maintained in spaced relation to the inner boiler shell by said connections; a closure ring for said chamber, a closure plate for said open end of inner boiler shell, at its junction with the outer shell, said plate provided with an opening in registry with the opening in said ring for the introduction of, fuel and air into the saidchamber, means to close and to heat'- insulate the space between the said ring and said plate, means providing for the circuitous passage of the combustion gases, from within said chamber, outwardly at the far end of said chamber, forwardly between said chamber outer surface and the surface of the inner shell, outwardly into the space beneath the outer shell, said space bounded by downward extension of the outer Walls of the boiler shell and continuous therewith and a bottom plate, rearwardly and outwardly from said space into narrow gas passes, one wall of which being the boiler outer shell and the extensions thereof and the other Walls comprising a plate provided with inturned flanges, means for securing said flanged plate in gas tight relation to said outer shell, means providing for the circuitous passage of the combustion gases through said narrow passages, one of said passages debouching directly into a gas exit, the other into a cross-wise disposed gas passage at one end and at the upper part of the boiler and thence to said gas exit.

3. A boiler as claimed in claim 2 provided with relief stay tubes passing through said boiler water compartment and connecting the gas passages within said inner boiler shell with the gas passages without said outer boiler shell, said tubes being of relatively short length as compared with their diameter, and providing a short-circuit passageway for combustion gases from a region of higher pressure to a region of lower pressure.

4. A boiler as claimed in claim 2 provided with a receptacle closed at its sides and bottom, open at its top, said top opening disposed immediately below the usual boiler water level, the outlet from said auxiliary water compartment emptying into the lower part of said receptacle; said receptacle providing a passage for the fluid from the auxiliary water compartment to the upper part of the boiler water compartment.

5. A boiler as claimed in claim 2, the closure plate for the open end of the inner boiler shell provided with means for the introduction of secondary air and means to admit said secondary air to the combustion chamber.

6. A boiler comprising an outer shell of cylindric lower form and of rectangular upper form, an inner shell of substantially hollow cylindric form open at one end, said end joined in steam and water tight relation to the outer shell, said outer shell being provided with a corresponding opening in one wall, said opening in registry with the open end of the inner shell, means for closing this opening, said inner shell closed at its other end and in spaced relation to the other walls of the outer shell, a combustion chamber within the inner shell, comprising a hollow, substantially cylindric, horizontally disposed refractory material chamber open at both ends, supported by a hollow substantially cylindric construction of tubes forming an auxiliary water chamber connected to the boiler water compartment at low and at high points, said connections providing for circulation of the water in the auxiliary water chamber with the boiler water, said chamber provided at one end with a closure ring, means for introducing fuel and air into said chamber from a fluid fuel burning device, a gas passage between the combustion chamber and the inner shell, into which the combustion gases pass from the combustion chamber, connecting passages between the said passage and the space beneath the outer boiler shell, openings fro-m said space to narrow gas passages disposed substantially vertically at the sides of the boiler, said narrow passages bounded on one side by the outer boiler wall, baffles disposed within said narrow passages directing the gases in a circuitous path toward a cross gas passage disposed at the upper part of the boiler and a gas exit.

'7. A boiler comprising an outer shell of rectangular section in its upper portion, cylindric in its lower portion, an inner shell of substantially hollow cylindric form closed at one end, open at the other, said open end joined to one wall of said outer shell provided with a registering opening therefor; said inner shell maintained by said joint in spaced relation to the other walls of the outer shell and in gas and water tight relation thereto, stays supporting the surfaces of the inner and outer shells, a boiler water compartment enclosed between said shells, provided with inlet and outlet, a combustion chamber comprising a substantially cylindric, horizontally disposed, refractory material chamber supported and maintained in spacedrelation within said inner shell by a hollow substantially'cylindric auxiliary water compartment of tubes, said com'- partment connected for continuous and open circulation with the boiler water compartment by inlet and outlet connections at high and at low points and maintained in spaced relation to the inner boiler shell by said connections; a closure ring for said chamber a closure plate for said open end of inner boiler shell at its junction with the outer shell, said plate provided with an opening in registry with the opening in said ring for the introduction oijfuel and airrinto said chamber, means to close and to heat-insulate the space between the saidl ring and said plate, means providing for the circuitous passage of the combustion gases, from within said chamber, outwardly atthe far end of said chamber, forwardly between said chamber outer surface and the surface'of the inner shell, outwardly into the space beneath the `outer shell, said space bounded by downward extension of the outer walls of the boiler shell and continuous therewith and a bottom plate, rearwardlyinto a narrow vertically disposed gas passage at the far end of the boiler, the walls of said gas passage comprising the rear boiler wall and the extension thereof and a plate vprovided with Vinturnedl anges, means for securing said flanged plate in gas tight relation yto said' outer shell; means providing for the circuitous passageof the combustion gases through said narrowpassage, said passage debouching'into a cross-wise gas passage disposed at one end toward the topoi the boiler and thence to a gas exit. l

8. A boiler as claimed in claim 7 provided with a side narrow, substantially vertically disposed, gas passageV and means to direct part of the gases into said narrow'gas pass from the space beneath the boiler and thence ina circuitous manner to said cross gas passage and to said gas exit. v v

9. A boiler comprising an outer shellv of cylindric lower form and of rectangular upper form, an inner shell of substantially hollow cylindric form open at one end, said end joined insteam and water tight relation to the `outer shell,lsaid outer shell being provided with a corresponding opening in one wall, said openin'g'in registry with the open end of the inner shell, means for partially closing this openingi said inner shell closed at its other end and in spaced relation' to the other walls Aof the outer shell, a combustion chamber, within said inner shell,"c`ornprising a hollow substantially cylindric, horizontally disposed refractory material chamber open at both ends, supported by a hollow auxiliary cylindric water compartment in spaced relation to the inner shell, said water compartment comprising an inner cylindric-shell, an outer cylindric shell forming a cylindric chamber between said shells the ends of said chamber closed by flat end rings, now-directing baffles extending from one end toward the other end lengthwise of` the hollow cylinder,`between the walls thereof, an inlet below said bafiies and an outlet above said baliles said inlet and outlet connected at high and atY low points with the boiler water compartment in continuous and lopen circulation therewith; said auxiliary water compartment connected for. circulation with the boiler at low and at high points,

said chamber provided at one end with a closure ring, means for introducing into said chamber, fuel and air from a iluid fuel burning device and means for' directing the combustion` gases from said chamber in a circuitous passage 'to a gas exit.

.10. A boiler comprising an outer shell of cylindric lower form and of rectangular upper form,

an inner shell of substantially hollow polygonal cross-section open at one end, said end joined in steam and water tight relation to the outer shell, said outer shell being provided with a corresponding opening in one wall, said opening in registry with the open end ofV the inner shell, means for partially closing this opening, said inner shell closed at its other end and in spaced relation to the other walls ofthe outer shell, a combustion chamberwithin the inner shell, comprising a hollow, substantially cylindric, horizontallydisposed refractory material chamber open at both ends, supported by a plurality of tubes, each tube connected at low and at high points with the boiler 'water compartment and providing circulation connection with the boiler i means to provide spaced relation of said chamber with the inner shell at its far end, aclosure'ring for the combustion chamber atits near end, a closure plate for said open end of inner boiler shell at its junction `with theouter shell, said plate provided with an opening in registry with theopening in the ring for the introduction of fuel and air into said combustion chamber, means to close and to heat-insulate the space between the combustion chamber ring and said plate; means to provide for the passage of the combustion gasesfrom within the chamberoutwardly at; the far end of the said chamber, forwardlybetween the curved portion of the U shaped tubes and the surfaceofthe inner shell, outwardly into the space beneath the outer shell, said V,space bounded by the downward extensionof the outer walls of the boilershell` and-continuous therewith, and a bottom plate; rearwardly and outwardly from said space into narrow gasY passes, one wall of saidv narrow gas passes being the boiler outer shell and the extensions thereof and the other walls comprising aplate provided with an inturned ilange; means for securing said flanged plate in gas tight relation to said outer shell; means providing for the circuitous passage of the combustion gases through saidl narrow passages, one of said passages debouching directly into a gas exit, the other into a crosswise disposed gas passage at one end and at the upper part of the boiler and thence to said gas exit, said outer boiler shell provided with screw threaded openings registering with the open ends of the U shaped tubes, screw threaded plugs closing said opening vand removably fastened plates covering openings. in the outer wall of said narrow gas passages permitting access to the threaded plugs and to the tube ends.

11. A boiler as claimed in claim 2 provided with an opening at one side, a steam-toliquid hot water heating system coil, comprising a manifold secured to said boiler with lower inlet and upper outlet chambers, and inlet and outlet connections to a hot water heating system, a plurality of tubes connecting, in open circulation, the lower and upper manifold chambers, the ends vof said tubes being fixed in a plate. forming the inner' side ofthe manifold, and closing said opening, said hot water heating4 system coil adapted to be positioned within` the said boiler in the upper portion of the steam space thereof, said steam space provided with a baffle separating the lower portion of the steam space from the upper portion and means to provide connection between said upper and lower steam spaces.

12. A boiler as claimed in claim 2 provided with an opening in one outer wall, a hot water supplyfcoil with inletV and outlet tubes passing through a supporting plate closing said opening, said hot water supply coil adapted to be p0- sitioned within saidV boiler and submerged in the water thereof, said inlet connected with a Water supply source, said outlet connected with a hot Water supply system, and said boiler provided with a second opening in one side wall, a steam-to-liquid hot water heating system coil, comprising a manifold secured to said boiler. with lower inlet and upper outlet chambers, and inlet and outlet connections to a hotwater heating system, a plurality of tubes connecting in open circulation the lower and upper manifold chambers: the ends of said tubes being fixed in a plate forming the inner side of the manifold and closing said second opening, said hot water heating system coil adapted to be positioned within the said boiler in the upper portion of the steam space thereof, said steam space provided with a baille separating the lower portion of the steam space from the upper portion and means to provide connection between said upper and lower steam spaces.

13. A boiler as claimed in claim 2 provided with a steam-to-liquid hot water heating system coil, with inlet and outlet tubesv passing through one wall of the boiler, said heating system coil.

positioned within the boiler, in the steam space thereof and connected with the inlet and the outletto a hot water heating system, said steam space provided with a baffle separating the lower portion of said steam space from the upper portion, means to provide connection between said upper and lower steamspaces, and means to provide air relief for the said steam spaces.

14. A boiler as claimed in claim 2 provided with a hot water supply coil, with inlet and outlet tubes passing through one wall of the boiler, said hot water coil positioned within the boiler and submerged in the water thereof, said inlet connected with a Water supply source, said outlet connected with a hot water supply system, said boiler further provided with a steam-toliquid hot water heating system coil, with inlet and outlet tubes passing through one wall of the boiler, said heating system coil positioned within the boiler, in the steam space thereof, and connected with the inlet and the outlet of a hot water heating system, said steam space provided with a baille separating the lower portion of said steam space from the upper portion, means to provide connection between said uppery and lower steam spaces, and meansto provide air.

relief for the said steam spaces.

MORA S. HALL. 

